For TTGO LoRa32 V2.1.6 you need to specify 23 (GPIO23) for LoRa RST and not 12.
(The iconst must be a typo.)
Read the start post of Big ESP32 + SX127x topic part 3 for details.
I have updated it for TTGO LoRa32 V2.1.6 (aka T3 V1.6).
Also check the notes about manual wiring of DIO1.
When DIO1 is not wired or not properly mapped in the software then downlinks will not work and hence OTAA will not work.
I am not aware if DIO1 is already wired to GPIO33 on the PCB by default and if DIO2 is already wired to GPIO32 on the PCB by default or not.
I do not have the V2.1.6 board so I am unable to verify it. If you could check with a multi-meter (in resistance/Ohms setting) if these are already connected on the PCB and report the results here that would be nice.